Protection of psbAII transcript from ribonuclease degradation in vitro by DnaK2 and DnaJ2 chaperones of the cyanobacterium Synechococcus elongatus PCC 7942.

Abstract

Three dnaK genes and four dnaJ genes have been identified in the genome of cyanobacterium Synechococcus elongatus PCC 7942. Among them, DnaK2 and DnaJ2 are induced by several stresses. Our yeast two-hybrid analysis revealed the specific interaction between DnaJ2 and RNase E, which is an essential endoribonuclease and involved in the regulation of psbAII in cyanobacteria. We examined the effect of DnaK2 and DnaJ2 on RNase E activity, monitored by the digestion of psbAII transctipt in vitro. Addition of DnaK2 and DnaJ2 obviously inhibited the RNase E activity in the ATP-dependent manner. These results suggest that DnaK2 and DnaJ2 are involved in the RNA degradation through interacting with RNase E.